Seoul: Science Minister Bae Kyung-hoon visited an office of South Korea's No. 2 mobile carrier KT Corp. on Thursday, calling for an all-out effort to address a recent series of unauthorized mobile payments.

According to Yonhap News Agency, the visit came after a total of 278 cases of unauthorized mobile payments worth 170 million won (US$122,000) had been reported by KT users as of Wednesday, raising concerns over a possible leak of customer data.

"The latest breach is a significant issue that directly affects people's trust in the telecommunications system in their daily lives," Bae stated. He emphasized the need for "all-out efforts to regain the public's trust" and underscored the importance of strong security as a critical factor in positioning the country among the world's top three players in the artificial intelligence sector.

Bae also called on the company to proactively cooperate with the related investigation. On the same day, KT announced that the personal data of more than 5,500 users might have been compromised in the breach, issuing a public apology for the failure.

"Hackers may possess additional personal data beyond the international mobile subscriber identity (IMSI) information of the affected KT users," the minister mentioned. He assured that the government would establish fundamental countermeasures and that findings would be announced once the investigation is complete.

KT explained that the IMSI data might have been exposed through illegal, unregistered micro base stations connected to its communication network. IMSI data, a unique identifier for each subscriber stored in a universal subscriber identity module (USIM) chip, can be misused if leaked.

Since August 27, some KT users, primarily in southwestern Seoul, have reported unauthorized mobile transactions. On Tuesday, the science ministry launched a special team to probe the recent breach, a day after KT officially reported the case to the Korea Internet and Security Agency.